Sexually Transmitted DiseasesPhase 4DOXY-PEPNCT05853120
Doxy-Post-exposure Prophylaxis
A Phase 4 study testing Doxycycline in people with Sexually Transmitted Diseases, run by Emory University at 1 site in United States.
Trial summary
The goal of this project is to collect data regarding the ability of various oral doses of doxycycline to penetrate mucosal tissues in men and women to inform the combination of doxycycline with antiretrovirals (ARVs) for the development of single-dose event-driven multipurpose prevention strategies to protect against… Read more about this study
- Who is it for?
- Ages 18 to 59 yearsHealthy volunteers can take part
- Conditions the study is for
- Sexually Transmitted Diseases
- What is being tested?
- Doxycycline
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 45 participants
- Where
- 1 siteUnited States
- Study dates
- 31 May 2023to 24 Dec 2024
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 59 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Aged 18-59 years
- Assigned male sex or female sex at birth
- In good general health
- Not currently taking doxycycline or other tetracycline-derived antibiotics and no plans to initiate during the study
- For HIV-positive people, on stable antiretroviral therapy with an undetectable viral load and CD4 count> 300ul/ml
- Willing to use condoms consistently for the duration of the study
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- Able to provide informed consent
- No plans for relocation in the next 4 months
- Not pregnant and does not plan on getting pregnant for the duration of the study
- Willing to undergo peripheral blood, urine, rectal or vaginal secretion collection, and a rectal or vaginal and cervical biopsy procedure
- Willing to use study products as directed
Who cannot join
- Current or chronic history of liver disease
- Continued need for, or use during the 90 days before enrollment, of the following medications:
- Systemic immunomodulatory agents
- Supraphysiologic doses of steroids (short course steroids less than 7 days duration, allowable at the discretion of the investigators)
- Chemotherapy or radiation for treatment of malignancy
- Experimental medications, vaccines, or biologicals
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- Intent to use doxycycline or other tetracycline-derived antibiotics during the study, outside of the study procedures
- Any other clinical condition or prior therapy that, in the opinion of the investigator, would make the patient unsuitable for the study or unable to comply with the study requirements
- Known allergic reaction to study drugs.
- Significant laboratory abnormalities at baseline visit for rectal biopsies, including but not limited to:
- Hgb ≤ 10 g/dL
- PTT > 1.5x ULN or INR > 1.5x ULN
- Platelet count <100,000
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Doxy-PEP: Dose-Ranging Study of Persons Receiving Doxycycline
The goal of this project is to collect data regarding the ability of various oral doses of doxycycline to penetrate mucosal tissues in men and women to inform the combination of doxycycline with antiretrovirals (ARVs) for the development of single-dose event-driven multipurpose prevention strategies to protect against HIV and sexually transmitted infections (STIs).
This study is of importance in the field of research because it allows the exploration of new dosing strategies that would permit a single event-driven oral dose of medications that could provide protection from HIV as well as other STIs.
Read more
The study population that this study seeks to enroll are healthy people assigned male or female sex at birth and not using gender-affirming hormone therapy and are willing to undergo study procedures.
Recruitment: Both face-to-face and online engagements will be conducted to recruit study participants. Face-to-face locations include bars and nightclubs, community organizations serving study populations, sports events, and community venues, and online engagements include dating sites, social networks, and craigslist, amongst other social medial platforms.
Read the detailed description
The incidence of bacterial STIs is increasing and studies have recently shown that Doxy-PEP can reduce the incidence of bacterial STIs among men who have sex with men (MSM) and Doxy-PEP is being explored for STI prevention among women.
A better understanding of mucosal drug penetration of doxycycline will inform the design of future studies to prevent STIs in various populations. The purpose of this study is to understand how well doxycycline taken by mouth gets to the tissues of the rectum and vagina. Researchers think doxycycline could be used to treat sexually transmitted infections (STIs) caused by bacteria. To understand better, they want to see how well doxycycline reaches the tissues affected by STIs.
The study procedures include the collection of past and present medical history, and biological specimen sampling such as blood, rectal and vaginal fluids, tissue biopsies, and urine. Study participants will also be administered an investigational agent (doxycycline not yet approved for this indication).
The duration of this clinical trial for study participants will be approximately 8 weeks.
- Conditions
- Sexually Transmitted Diseases
- Being tested
- Doxycycline
- Keywords
- Prevention, STI, Post-exposure prophylaxis, HIV, PEP
- Medical subject headings
- Sexually Transmitted Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DoxycyclineDrug
Also called DOX
Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
| Study group | Role | What they receive |
|---|---|---|
| Doxycycline 100 mg | Active comparator | Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10. Receives: Drug: Doxycycline |
| Doxycycline 200 mg | Active comparator | Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10 Receives: Drug: Doxycycline |
What is being measured
The primary outcome is the main question the study is designed to answer.
Doxycycline Concentrations in Rectal Tissues
Rectal biopsies were collected 24 hours after administration of the initial dose of doxycycline
Measured: Day 2
Doxycycline Concentrations in Vaginal Tissues
Vaginal biopsies collected 24 hours after administration of the initial dose of doxycycline
Measured: Day 2
Doxycycline Concentrations in Rectal Tissues After the Fifth Dose of Doxycycline
Self-collected swabs and rectal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Measured: Day 15
Doxycycline Concentrations in Vaginal Tissues Collected 24 Hours After the Fifth Dose of Doxycycline
Self-collected swabs and vaginal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Measured: Day 15
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 May 2023
- Study start31 May 2023
- Primary completion25 Sep 2024
- Study completion24 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Sexually Transmitted DiseasesStudies of the same condition, open and under way.
- More trials run by Emory UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 45 participants (actual)
Sponsor and investigators
- Lead sponsor
- Emory University
- Sponsor type
- University, hospital or other
- Collaborators
- Centers for Disease Control and Prevention
- Responsible party
- Principal investigator, Colleen Kelley, Emory University
- Investigators
- Colleen Kelley, MD, MPH, Principal investigator, Emory University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05853120
- Sponsor's protocol ID
- STUDY00005552
- Other IDs
- 75D30122C14484
- Acronym
- DOXY-PEP
- Status last verified
- Sep 2025
- First submitted
- 2 May 2023
- Last updated
- 11 Sep 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data that underlie the results published for this study (including text, tables, figures, and appendices), will be made available for sharing, after de-identification.
Publications
Daly MB, Spandau M, Edwards TE, Dinh C, Fountain J, Dienhart JA, Conway-Washington C, Kelley C, Heneine W, Haaland R. Chelating anticoagulants reduce plasma doxycycline measurements: implications for doxy PEP monitoring. Expert Rev Clin Pharmacol. 2026 Jan-Feb;19(2):199-205. doi: 10.1080/17512433.2026.2632931. Epub 2026 Feb 19.
PubMed 41701614
Study at a glance
From the registry record, last updated by the sponsor on 11 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Doxy-PEP: Dose-Ranging Study of Persons Receiving Doxycycline
- ClinicalTrials.gov ID
- NCT05853120
- Acronym / sponsor ID
- DOXY-PEP / STUDY00005552
- Conditions
- Sexually Transmitted Diseases
- Keywords
- Prevention, STI, Post-exposure prophylaxis, HIV, PEP
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 45 participants (actual)
- Lead sponsor
- Emory UniversityUniversity, hospital or other
- Collaborators
- Centers for Disease Control and Prevention
- Study start
- 31 May 2023 (actual)
- Primary completion
- 25 Sep 2024 (actual)
- Study completion
- 24 Dec 2024 (actual)
- First posted
- 10 May 2023 (actual)
- Results
- Posted 11 Sep 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this project is to collect data regarding the ability of various oral doses of doxycycline to penetrate mucosal tissues in men and women to inform the combination of doxycycline with antiretrovirals (ARVs) for the development of single-dose event-driven multipurpose prevention strategies to protect against HIV and sexually transmitted infections (STIs).
This study is of importance in the field of research because it allows the exploration of new dosing strategies that would permit a single event-driven oral dose of medications that could provide protection from HIV as well as other STIs.
The study population that this study seeks to enroll are healthy people assigned male or female sex at birth and not using gender-affirming hormone therapy and are willing to undergo study procedures.
Recruitment: Both face-to-face and online engagements will be conducted to recruit study participants. Face-to-face locations include bars and nightclubs, community organizations serving study populations, sports events, and community venues, and online engagements include dating sites, social networks, and craigslist, amongst other social medial platforms.
Detailed description
The incidence of bacterial STIs is increasing and studies have recently shown that Doxy-PEP can reduce the incidence of bacterial STIs among men who have sex with men (MSM) and Doxy-PEP is being explored for STI prevention among women.
A better understanding of mucosal drug penetration of doxycycline will inform the design of future studies to prevent STIs in various populations. The purpose of this study is to understand how well doxycycline taken by mouth gets to the tissues of the rectum and vagina. Researchers think doxycycline could be used to treat sexually transmitted infections (STIs) caused by bacteria. To understand better, they want to see how well doxycycline reaches the tissues affected by STIs.
The study procedures include the collection of past and present medical history, and biological specimen sampling such as blood, rectal and vaginal fluids, tissue biopsies, and urine. Study participants will also be administered an investigational agent (doxycycline not yet approved for this indication).
The duration of this clinical trial for study participants will be approximately 8 weeks.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Doxycycline 100 mg | Active comparator | Drug: DoxycyclineDoxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10. |
| Doxycycline 200 mg | Active comparator | Drug: DoxycyclineDoxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10 |
Who may qualify
- Ages
- 18 to 59 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (11 listed)
- Aged 18-59 years
- Assigned male sex or female sex at birth
- In good general health
- Not currently taking doxycycline or other tetracycline-derived antibiotics and no plans to initiate during the study
- For HIV-positive people, on stable antiretroviral therapy with an undetectable viral load and CD4 count> 300ul/ml
Key exclusion criteria (13 listed)
- Current or chronic history of liver disease
- Continued need for, or use during the 90 days before enrollment, of the following medications:
- Intent to use doxycycline or other tetracycline-derived antibiotics during the study, outside of the study procedures
- Any other clinical condition or prior therapy that, in the opinion of the investigator, would make the patient unsuitable for the study or unable to comply with the study requirements
- Known allergic reaction to study drugs.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| DoxycyclineAlso: DOXDoxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses. | Drug | Doxycycline 100 mg, Doxycycline 200 mg |
Primary outcome
Doxycycline Concentrations in Rectal Tissues
Time frame: Day 2
Rectal biopsies were collected 24 hours after administration of the initial dose of doxycycline
Doxycycline Concentrations in Vaginal Tissues
Time frame: Day 2
Vaginal biopsies collected 24 hours after administration of the initial dose of doxycycline
Doxycycline Concentrations in Rectal Tissues After the Fifth Dose of Doxycycline
Time frame: Day 15
Self-collected swabs and rectal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Doxycycline Concentrations in Vaginal Tissues Collected 24 Hours After the Fifth Dose of Doxycycline
Time frame: Day 15
Self-collected swabs and vaginal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Sep 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41701614Daly MB, Spandau M, Edwards TE, Dinh C, Fountain J, Dienhart JA, Conway-Washington C, Kelley C, Heneine W, Haaland R. Chelating anticoagulants reduce plasma doxycycline measurements: implications for doxy PEP monitoring. Expert Rev Clin Pharmacol. 2026 Jan-Feb;19(2):199-205. doi: 10.1080/17512433.2026.2632931. Epub 2026 Feb 19.
- Individual participant dataSharing planned: Yes. Individual participant data that underlie the results published for this study (including text, tables, figures, and appendices), will be made available for sharing, after de-identification.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Colleen Kelley, MD, MPH principal investigator
Emory University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Doxycycline in people with Sexually Transmitted Diseases, run by Emory University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 11 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 11 Sep 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Doxycycline Concentrations in Rectal Tissues (time frame: Day 2). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05853120, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Sep 2025.